Apparatus for detwisting metal sections



April 11, 1944. 'LAK 2,346,43

APPARATUS FOR DETWISTI NG METAL SECTIONS Q Filed Sept. 17, 1941 .5 Sheets-Sheet l April 11, 1944; N c K 2,346,438

APPARATUS FOR DETWISTING METAL SECTIONS Filed Sept. 17, 1941 5 Sheets-Sheet 2 April 11, 1944. N. c. LAKE APPARATUS FOR DETWISTING METALSECTIONS 5 Sheets-Sheet 3 Filed Sept. 17, 1 941 April 11, 1944. Ni Q LAKE 2,346,438

APPARATUS FOR DETWISTING METAL SECTIONS Filed Sept. 17, 1941 5 Sheets-Sheet 4 April 11, 1944. K 2,346,438

APPARATUS FOR DETWISTING METAL SECTIONS Filed Sept. 17, 1941 5 Sheets-Sheet 5 4 2 vQvl-lbrn e ys Patented Apr. 11, 1944 APPARATUS FOR nn'rwrs'rme METAL snorrons Norman Cecil-Lake, Stockton on-Te'es, England,

assignor to Head, Wrightson &Company, Limited, Thornaby-on-Tees,"England Application September 17,1941, Serial No. 411,229 In Great Britain August 15, 1940 Claims.

This invention relates to improvements in apparatus for de-twisting metal sections.

In the extrusion'of sections there is frequently a twist caused by the relative flow of the material during the extrusion operation. This twist may or may not be uniform throughout the length of the section. Slight variations in the temperature at various points in the billets or in the die friction will cause variation in the degree of twist as the'sections progress through the die.

It has been suggested that this twist might be removed by the application of a de-twisting head to one or both of the'gripper heads of a section stretching machine, but since in stretching it is necessary to grip the sections at their extremities it is not possible to apply a varying amount of detwisting throughout the length of the section.

Since the application of de-twisting to a section stretcher will increase the time required for han dling each section, it follows that more machines are required, and these machines are expensive and take up a considerable amount of floor space. By the provision of a separate de-twisting unit according to the present invention it is possible to arrange-for short or long lengths of a section to be de twisted according to the variation in the twist.

The apparatus according to the invention comprises a frame in which are mounted two heads for gripping the metal section, one having a rotatable gripper adapted to be connected to driving'rneans, and the other being free to move longitudinally towards and away from the rotatable gripper to allow for variations in length of a section in the course of the de-twisting operation.

Preferably, means are provided for adjusting the position of the longitudinally movable head to deal with varying lengths of section.

The frame is preferably arranged symmetricab, 1y about the de-twisting axis, the body of the head having th rotatable gripper being rigidly mounted in the frame, and the frame providing guiding means for the movement of the longitudinally movable head whilst restraining rotation thereof- Either or both grippers may have one or more e. unyielding, when jaws which are fixed, i. moved to the operative position, e. g. areflmoved into position by a screw device, and one or. more jaws which are not fixed, i. e. are yieldable'under pressure in the operative position, e. g. are moved into position by fluid pressure. Thereby accurate alignment of the jaws in the two grippers is obtainable or is facilitated.

' A conveyor may be provided on the entry sideofthemachirieand thisis preferably provided,

with means for raising and lowering so as to enable the conveyor to be lowered clear of the section whilst dc-twisting i taking place so as to avoid damage to the section, and raised on completion of the de-twisting operation to such a level as will permit the section to be fed further into the machine for the next stage of de-twisting. The means for raising and lowering the conveyor maybe interconnected with the means for actuating the gripper jaws.

Preferably thereare also provided rollers for supporting a section in its travel through the gripper heads, which rollers are automatically brought into and out of operation when the gripper jaw are opened and closed.

An embodiment of the invention is shown on the accompanying drawings, of which:

Figure 1 shows the apparatus including a delivery conveyor in elevation, I

Figure 1 is an illustration of the feeding table which is positioned and used in the apparatus of Figure 1 at the left thereof,

, Figure 2 is a plan of the parts of Figure 1,

t Figure 2 is a plan of the feeding table of Figm Figure 3 is a sectional elevation, on a larger scale showing the de-twisting apparatus in more detail,

Figure 4 is a plan of Figure 3,

Figure 5 is a section of Figure 3, taken on the line A-A.

Figure 6 is a section of Figure 3 taken on the line B-B and Figure 7 is an end elevation of Figure 3 looking in the direction C--C. I

A de-twisting head A is firmly located both transversely and longitudinallyin a frame B of structural steel or cast construction in which a moving head C is arranged to travers longitudinally.

The de-twisting head consists of a cast outer body D bored to receive a rotating gripper holder E in which are mounted two, three or four gripperblocks F faced with polished metal or fabric gripping surfaces G and moved in and out in a radial direction by wedges H provided with a dove-tail slide I so as to ensure the positive movement of thegr pperblocks. One or mor of the wedges is operated by a cylinder J and piston K using compressed air or-other pressure fluid as an operating medium.

"Preferably, as already indicated, one or more of the wedges is moved by .positive drivingmeans such as a nut L and screwM, so that one or two of the gripper of jaw blocks will be positioned by means of the screw operated wedges whilst the remaining gripper blocks are operated by fiuid pressure. This enables the alignment of the gripping surfaces to b maintained in both the de-twisting and the moving heads, leaving the gripping and releasing to be achieved by means of fluid pressure in the cylinders. J. By arranging the gripper blocks to move radially relative motion between the gripping surfaces and the section is avoided and consequently mechanical damage to the surface of the section is obviated. .7 V. To ensure freedom of rotation the rotating gripper holder is mounted on a number of ba l bearing rollers N mounted in the outer body D.

The gripper holder is secured to aspilr gear ring in engaging an idler pinion P mounted on an intermediate shaft Q and engaging with a driving pinion R. e

In line with the shaft of the pinion R, is the output shaft of a gear reduction unit S and this is coupled to the pinion shaft by means of a clutch T; r

v r h 'The gear unit S may be of a spur, worm or heliocentric type and will be driven through a flexible coupling from an electric motor U.

The motor U and gear S may be mounted either upon a separate bedpl-ate alongside the machine or in any other convenient position.

It is preferred, as shown, to mount the driving gear S and motor U on top of the frame B. The operating lever SI for the clutch T may be arranged in any convenient position for example as shown in Figure 1.' When de-clutched, the gripper holder has complete freedom of rotation.

For obtaining, anindication of the degree of twist in the section and the angle of de-twist which is performed in operation, a suitable pointer V is attached (see Figure 5) to the gripper holder E, whilst the outer body D is provided with graduated markings W on the inside surface adjacent to the pointer.

The gripper holder 3 carries one or more air cylinders X each with a piston whose rod at its upper extremity carries a roller Y. This cylinder or cylinders is provided with means of vertical adjustment, and the piston hasea limited stroke so that the roller in the lower position will be just below the level of the screw operated gripper blocks, and in the upper position will be sufficiently above the level of the gripper blocks to ensure that the section in its travel through the gripper heads has a clear path. Preferably the number of cylinders and rollers corresponds to the number of screw operated gripper, blocks. The cylinder or cylinders are intercoupled with the cylinders actuating thefluid pressure oper-. ated gripper blocks so that when the gripper blocks are out of operation the rollers will have lifted the section in readiness for its endwise movement. Conversely, when the section is gripped, the rollers will be out of operation. The frame B to which the outer body of the rotatable gripper is rigidly attached is prefer ably arranged with four longitudinal members so disposed about the axis of the machine as to give complete freedom of access to the section. 'In order to give the maximum accessibility to the section it is preferable to arrange for thelong itudinal members to be as close as is possible to the vertical axis consistent with obtaining the necessary resistance to the torque induced by the de-twisting action, Such arrangement is shown in the drawin s. H V

The moving head C carrying the non-rotatable gripping means is similarly provided with gripper blocks, actuating wedges, and the fluid pressure cylinders and the screw device for operating the wedges. It is likewise provided with one or more supporting rollers with adjustable fluid pressure cylinders for bringing the rollers into and out of operation. This is not shown in the drawings.

The moving head is mounted on ball bearing wheels Z and is provided with steadying rollers Al bearing on the main frame B. These rollers are adjustable so as to restrict the angu ar movement of the head to a minimum.

During the de-twisting operation the moving head C will be entirely free to move longitudinally as the section changes length, i. e. as it lengthens and shortens in the course of the detwisting operation. For causing the head to traverse along the longitudinal bed to deal with varying lengths of section a hand wheel A2 is provided that operates through gearing upon sprockets engaging a fixed chain (not shown). Alternatively a rack and pinion traversing arrangement may be employed; or the head may be moved by means of an electrically driven nii a In'order to enable the rotatable gripper to be balanced so as to reduce the inertia effect and to give an accurate indication of the relative twist in the section, the inlet piping to the cylinders on the rotating gripper is arranged as follows:

Airfrom thecompressed air main is fed into a 4-wayvalve A3. From this valve two pipes are led away one (A l) feeding the outer ends of the fluid pressure cylinders actuating the gripper blocks, and the other (A5) feeding the inner end of these cylinders. The pipe A4 is fed through a. rotating connection into the centre of an" axle carrying a drum A6. From the hub .of this drum a, flexible pipe A'l is taken radially and curved around a guide until it reaches the periphery of the drum A6 where it continues to be curved until it is taken tangentially from the drum upwards to feed a manifold A v I From' this manifold one or more pipes A9, according to the number of cylinders-two being shown in the drawings-are led to the outer ends of the cylinders J connected at J I. The other pipe Ais also ledthrough a radial connection into the centre of the hub of the drum A6, and a flexible pipe All] is taken radially from the hub and wrapped around the drum A6 in the op posite direction and cou led to the manifold A8. From this manifoldAB' pipes All are led to the cylinders J and coupled to the inner ends at points J2. he manifold A8 and the bore bf the hub of the drum A6 are divided so. as .to isolate the connection A4 from. connection A5. f

.Guides are providedonthe rotating gripper to ensurethat a constant tension is maintained i h 'pipes'. A! and All]. rotating the i0- tatable gripper holderE, the flexible pipes A1. and Al 0 will wind onto and unwind from the A6.

In order to balance the Weight of the manifold A8, a balance weight or weights A12 is added td All] due to excessive angular movement of the r6 tatable gripperliolder E, limit-switches AI3 are provided at two points and these will stop the driving motor U. c

When at the commencement of a shiftit is nee essary to rotate the gripper holder a number of times in order to ensure that it is entirely free to rotate under the action or the section, the.

' To avoid damage to the flexible pipes Aland pipes A1 and All! may be readily uncoupled and the limit switches AIS isolated by a push button. As it is desirable that the rotating gripper holder E should be able to rotate through 180 or: as near as possible, when de-twisting, limit switches AI3 and the lengths of the flexible pipes Aland AID are arranged to give this movement.

A pipe is taken from one of the connections All and coupled to the underside of the pistons X controlling the carrying rolls Y.

From the air pipe A4 a branch A14 (Figure 4) is taken and coupled to one end of v the :air cylinder Cl controlling the raising and lowering of the inlet conveyor C2. The action of this is'to admit pressure to one side of the piston and cause the conveyor to lower when the gripper blocks are moving into contact with the section.

A branch M is taken from pipe A5 in a similar way and coupled to the other end of the cylinder in such a way as to raise the conveyor when the gripper blocks are being released.

Since the gripper blocks on the moving head C do not rotate, the air connections are of a simple character and are coupled to a 4-way valve of accepted design. These need not be described.

On the entry side of the de-twister a conveyor C2 is provided and this is arranged to raise to a position in which the section will be clear of the gripper blocks when feeding sections into the machine and lowered to a position well clear of the section whilst the latter is rotating.

The preferable arrangement for this table, which is shown in Figures 1 and 2, is one in which the conveyor C2 is raised and lowered by means of an air cylinder Cl intercoupled with the valve operating the gripper block cylinders J.

In this preferred arrangement, two bell crank levers C3 are coupled by links C4 to the cylinder Cl and for the other arms of the bell crank levers C3 to be coupled to vertical bars C5, coupled at their upper extremities to the conveyor C2.

Long and rigid guides C6 are provided for the bars C5 and are mounted upon a rigid frame 01.

A stroke limiting device would be included so as to prevent the conveyor from lifting a section so high that it would foul the top gripper blocks.

On the exit side of the de-twister, there is provided a conveyor table GI, the height of which may be adjusted to suit the dimensions of various sections. This is suitably carried out by means of screws and bell crank levers operated by wheel G2 as indicated in Figures 1 and 2.

In operation, a section is placed upon conveyor C2 which is in its raised position, this position having been determined by the stroke limiting mechanism.

The section is pushed towards the gripper jaws in the rotating gripper holder E. The operator then presses the forward or reverse push button controlling the motor U so as to rotate the gripper holder E and the gripper jaws F to bring them into line with the end of the section to be de-twisted.

The operator continues to push the section along the conveyor C2 and through the gripper head D until he observes a change in the degree of twist. He then operates the air valve A3 causing the pistons K to move forward bringing the gripper blocks F into contact with the section. The screw operated blocks will have been previously set to suit the section being dealt with.

The section is now centrally disposed about its axis and the head is rotated by means of the motor U until the end of the section is in a position in which it will enter the gripper jaws of the moving head C. Having entered sufficient of the section to grip, the air valve Al 4 on the gripper head C is operated so as to bring the gripper blocks in this head into contact with the section.

The operator then observes from the position of the pointer V on the scale W, the amount of twist in the section, and he then presses the forward or reverse push button controlling the motor U and continues to depress'this until the pointer indicates a sufiicient degree of antitwist to remove the original twist from the section. He then disengages the clutch T and the stored energy in the section rotates the rotating gripper holder E until the section has returned to its natural position. If, having reached this position, thepointer V still indicates the presence of a twist the operator repeats the movements described above, taking the rotating gripper head through a further angular movement in order to remove the remaining twist.

Having satisfactorily removed the twist in this operation of the section, the operator releases the grips in both heads, causing the conveyor C2 and the rollers Y to aise the section clear of the fixed gripper blocks. The section is then pushed through the two heads, the rotating l l pper holder E being rotated to facilitate the passage of the de-twisted portion through the head D.

The process is then repeated as previously described until the whole of the twists in the section have been removed.

On emergence from the moving head 0, the sections will be delivered on to a conveyor GI, the height of which will have been adjusted to suit the section being dealt with.

What I claim is:

1. Apparatus for de-twisting metal sections comprising a frame, a first gripping head having an outer body rigidly mounted in said frame and a rotatable gripper holder, a second gripping head, the rotatable gripping holder being open for insertion of the sections through the rotatable gripping holder at the end opposite to the second gripping head, means for preventing rotation of said second gripping head while leaving it free to travel towards and from said first gripping head under the action of a section being detwisted resulting in a tendency to change the length of said section, said means comprising wheels carried by said second gripping head and bearing Vertically on said frame, and steadying rollers bearing laterally on said frame, and a gripping holder fixed in said second gripping head.

2. Apparatus for de-twisting metal sections comprising a frame, a gripping head having an outer body rigidly mounted in said frame, a gripper holder rotatably mounted in said gripping head, the rotatable gripping holder being open for insertion of the sections through the rotatable gripping holder at the end opposite to the second gripping head, driving means for rotating said grippe holder, reversible driving connections operatively connecting said driving means with said gripper holder and including a clutch for disconnecting said driving means at Will to thereby leave said gripper holder free to be return rotated by energy stored up in a detwisted section, and a second gripping head mov able longitudinally along said frame.

3. Apparatus for de-twisting metal sections comprisinggripping heads, having gripper hold-'- ers, one of which is rotatable and open for passage of the sections into one end and out of the other end of'the holder, gripper blocks in said gripper holders, means for actuating a gripper block in the rotatable gripper holder, an entry conveyor for sections to be de-twisted, means for raising and lowering said conveyor, and an intercoupling between the two said means.

4. Apparatus for ole-twisting metal sections comprising gripping heads, having gripper holders, One of which is rotatable and open for passage of the sections into one end and out of the other end of the holder, gripper blocks in said gripper holders, means for actuating a gripper block in the rotatable gripper holder, rolling supports intermediate said gripping heads, means for' raising and lowering said rolling supports, and an intercoupling between the two said means.

5. Apparatus for de-twisting metal sections comprising a gripping head, a gripper holder rotatably mounted in said gripping head, a gripper block in said gripper holder, a fluid pressure operated cylinder and piston device operatively connected to said gripper block, means mounting said device on said gripper holder eccentrically to the axis of rotation thereof, and means for supplying pressure fluid to said piston and cylinder device comprising a rotatable drum having an axle and a hub in fluid communication with each other, a fluid-conveying flexible pipe entrained around the-rotatable drum and providing communication between the drum hub and the piston and cylinder device, and means for supplying pressure fluid to the drum axle.

NORMAN CECIL LAKE. 

